1. Field of the Invention
This invention relates to a nail-driving device, and more particularly to a nail-driving device that includes a safety unit.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a conventional nail-driving device 1 includes a nail ejection seat 11, a safety member 12 movable relative to the nail ejection seat 11 in a nail-driving direction, a magazine 14 connected to the nail ejection seat 11 for receiving a plurality of nails 13, and a trigger unit 15 operable to fire the nails 13 from the nail ejection seat 11 one at a time. The safety member 12 has a pressing portion 121 movable within the nail ejection seat 11, and a contact portion 122 movable to contact the trigger unit 15 so as to allow for firing of one nail 13. If the contact portion 122 of the safety member 12 is not in contact with the trigger unit 15, any operation of the trigger unit 15 cannot result in firing of one nail 13. One of the nails 13 is disposed within the nail ejection seat 11, and has a tip 131 protruding farther from the nail ejection seat 11 along the nail-driving direction than the pressing portion 121 of the safety member 12.
To fasten a workpiece 2 in the form of a metal plate onto a wooden member (not shown), such as a wooden plate, one or more nails 13 are moved respectively through nail holes 21 (only one is shown) in the workpiece 2, and are driven into the wooden member. During a nail-driving operation of the nail-driving device 1, the pressing portion 121 of the safety member 12 is pressed against the workpiece 2 to move the nail 13 into the corresponding nail hole 21 in the workpiece 2. Hence, the contact portion 122 of the safety member 12 comes into contact with the trigger unit 15 to switch the nail-driving device 1 to a firing-allowable state. Subsequently, the trigger unit 15 is operated to drive the nail 13 into the wooden member.
The aforesaid conventional nail-driving device 1 has a drawback. That is, the maximum distance traveled by the safety member 12 relative to the nail 13 is limited. Thus, if the workpiece 2 is thick, for example, if the thickness of the workpiece 2 is about 4.5 mm, when the safety member 12 is pressed against the workpiece 2 and when the nail 13 is moved into the corresponding nail hole 21 in the workpiece 2, the nail 13 may not be able to contact the wooden member. If this occurs, when the nail 13 is driven into the wooden member by the nail-driving device 1, the portion of the nail 13 extending into the wooden member will be too short to fasten the workpiece 2 firmly to the wooden member.